You are correct they are Oribatid mites, very common if you look for them hard enough. They won’t eat your seedlings, there are plenty in my seedling trays. Leave them be, and relax

15C?! You need a few orchids Ralph

The Begonia certainly looks like virus infection, there are viruses that cause ring spots like that. Ring spotting fungi end up with necrosis at the centre with fungal fruiting bodies, so I think virus the most likely cause. The Lepismium could be thrips, the shoots are usually damaged when young an...

Lovely, what temperature do you keep your Disocactus at?

Oreocereus trollii

My two flowering size Melocacti have been confusing me the last few days by opening flowers around 7pm, which seems very odd to say the least. Usually the flowers open in the day.
Here is Melocactus matanzanus this evening, Melocactus violaceus has been up to it as well...

Thanks for posting that Paul, interesting (but rather depressing) reading

In my experience they are very partial in their attacks on plants. Some can be really badly affected, whilst others are barely touched. Opuntioid cacti seem particularly affected, particularly the flowers where the outer petals can be damaged enough to fuse the flower parts together stopping the flo...

That orange one is superb Ralph, definitely going on my wish list!!

Thanks I will look out for those Orius! I gave up using chemicals for control of thrips last year. They always come back eventually, the eggs are partially protected by being inserted in the hosts epidermis, and the pupal stage is in the compost which makes effective control by contact insecticides ...